sql: increment VIEW counter for tables within sub-select

VIEW can be created not only in form of AS SELECT but also in form of AS
VALUES (...). In the latter case space's view reference counters were
not incremented. Furthermore, if view came with sub-select, reference
counters of tables within sub-select were not updated as well. These
problems occurred due to simplified traverse over AST: only tables
within FROM clause were accounted. This patch fixes them introducing
complete pass over AST using walker.

Closes #3815